Helmet



FIG. 1 is a perspective view of a helmet;

FIG. 2 is a front elevation view thereof;

FIG. 3 is back elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines shown in the drawings depict portions of a helmet and a facemask that form no part of the claimed invention. 

CLAIM The ornamental design for a helmet, as shown and described. 